PPRuNe Forums - View Single Post - Long Range vs Max Range Cruise
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Old 16th July 2001 | 18:19
  #6 (permalink)  
quid
still learning....
 
Joined: Jul 1999
Posts: 169
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From: USA
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I'm afraid I have to disagree on the speeds, gents.

LRC is about 5-6% faster (TAS) than the best specific (optimum) range. For this increase you pay about a 1% penalty in range. Max (optimum) range is a very stable speed, only a few knots indicated less than LRC.

Min drag (L/D max, or max endurance) is MUCH slower than max range. It is speed unstable if you get on the back side of it. Generally your holding speeds are 5-10% faster then L/D max to increase speed stability.

Wtih the fuel on board, you can do only two things. Either maximize your hours and minutes until flameout - max endurance. Or, maximize the miles you can fly - max range. Any other speed is a compromize.

The industry has adopted LRC as an acceptable compromize. A 1% penalty for a 5% increase in speed (for schedule) makes sense.
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